Hello,
I recently called Theta and asked them about servicing my Data II and they said "no problem". They did warn me that it sounded like it needed a new laser and that costs 350 dollars. But it is reassuring to know that they will still gladly service a product that was introduced to the marketplace 12 years ago.
As for the Jade, I believe it was introduced in 2000, so the good news is that you will be buying, at most, a 4 year old player.
Good luck.
Tom
P.S. I noticed there are now 2 Jade's out there in the classifieds.